Coloboma of the Iris: Causes, Symptoms, and Treatment
Medically reviewed by Harsha Moole, MD, Internal Medicine. Last reviewed: October 23, 2026.
What kind of doctor treats coloboma of the iris?
A coloboma of the iris, a gap in the colored part of the eye that is usually present from birth, is managed by an ophthalmologist (eye doctor). A medical geneticist and a primary care doctor can also help coordinate care, since a coloboma can sometimes occur alongside other conditions. Colobomas of the iris generally do not lead to vision loss.
What is coloboma of the iris?
Coloboma of the iris is a hole or defect of the iris of the eye. The iris is the colored part of the eye. Most colobomas are present since birth. A coloboma of the iris can look like a second pupil or a black notch at the edge of the pupil. This gives the pupil an irregular shape. It can also appear as a split in the iris from the pupil to the edge of the iris. Iris coloboma can make the pupil look more like a keyhole or teardrop. Another name for it is keyhole pupil. Colobomas can affect 1 or both eyes.
Symptoms
Colobomas that affect the iris generally do not lead to vision loss. Some people with coloboma have no symptoms. Others may have problems with their vision, including sensitivity to light. A small coloboma may act like a second pupil and allow a second image to focus on the back of the eye. This may cause:
- Blurred vision.
- Double vision.
- A ghost image.
If the coloboma has been there since birth, the defect may include the retina, choroid, or optic nerve. Colobomas that involve the retina result in vision loss in specific parts of the visual field. People with coloboma may also have other eye problems, such as:
- Microphthalmia, which means unusually small eyes.
- Cataract, a cloudy area in the lens of the eye.
- Glaucoma, a group of eye diseases that can cause vision loss or blindness.
- Refractive errors, like nearsightedness or farsightedness.
Causes and who gets it
Most cases of coloboma have no known cause and are not related to other abnormalities. Some are due to a specific genetic defect. A small number of people with coloboma have other inherited developmental problems. A coloboma happens when a baby's eye does not develop normally during pregnancy. Around the second month before birth, a seam called the optic fissure closes to form the structures of the eye. When the optic fissure does not close completely, the result is a coloboma. Coloboma sometimes runs in families. Environmental factors, such as drinking alcohol during pregnancy, may also increase a baby's risk.
How doctors diagnose it
Most colobomas are diagnosed at birth or shortly afterward. The provider will take a medical history and do an exam. Because the problem is most often diagnosed in infants, knowing the family history is very important. The provider will do a detailed eye exam that includes looking into the back of the eye while the eye is dilated. An MRI of the brain, eyes, and connecting nerves may be done if other problems are suspected.
Treatment
Treatment cannot replace the part of the eye that is missing because of coloboma. But there are treatments that can help people make the most of their vision. These treatments can help:
- Glasses or contacts. People with refractive errors may need them to see more clearly.
- Colored contact lenses can make the pupils look rounder for people with iris colobomas.
- Surgery. People with iris colobomas sometimes get surgery to make their pupils look rounder.
- Low vision aids. If vision loss cannot be corrected with glasses or contacts, special devices can help you see better.
- Eye patch or eye drops. Children who have coloboma in only one eye may need these to prevent amblyopia (lazy eye).
Children and adults may need treatment for other eye conditions related to coloboma, such as cataracts or glaucoma.
When to see a doctor
Contact your child's health care provider if you notice what appears to be a hole in the iris or an unusual-shaped pupil. Also contact the provider if your child's vision slowly becomes blurred or decreased. Your child may also need to see an eye specialist, called an ophthalmologist.
A coloboma can involve the retina. Call 911 or go to the emergency room right away for sudden vision changes, such as a lot of new floaters, flashes of light, or a dark shadow or curtain over your vision. These can be signs of a detached retina, which is a medical emergency.
How a direct primary care or concierge doctor fits in
A direct primary care doctor charges a flat monthly fee instead of billing insurance, while a concierge doctor usually charges more and often works alongside insurance. This doctor can look at your child's eyes at a checkup and refer you to an ophthalmologist.
Common questions
Does an iris coloboma affect vision?
An iris coloboma generally does not lead to vision loss. Some people notice more sensitivity to light. A small coloboma may also act like a second pupil and cause blurred or double vision. Large retinal colobomas or ones that affect the optic nerve can cause low vision.
Can a direct primary care doctor manage an iris coloboma?
A direct primary care doctor can be your first contact if you notice what appears to be a hole in the iris or an unusual-shaped pupil. Your child may also need to see an eye specialist, called an ophthalmologist.
Is a coloboma of the iris inherited?
Sometimes. Coloboma sometimes runs in families. Most often, isolated coloboma is not inherited, and there is only one affected individual in a family.
Sources
- MedlinePlus - Coloboma of the iris
- National Eye Institute - Retinal Detachment
- National Eye Institute - Coloboma
- MedlinePlus Genetics - Coloboma
Medical Disclaimer
This content is for general educational and informational purposes only and is not medical advice. It is not a substitute for professional medical advice, diagnosis, or treatment, and reading it does not create a doctor-patient relationship. Always seek the advice of your physician or another qualified health provider with any questions about a medical condition, and never disregard or delay seeking professional advice because of something you read here. If you think you may have a medical emergency, call 911 (or your local emergency number) immediately.
